glass texturing - inside semi transp mat?

i made a bottle with some thickness
and use mirror and transp to get some refraction from the glass
and it looks very nice

1 - now should the normal on the inside faces be inward or outward ?

2- 1/2 transp inside faces
but at the base of the bottle i need to add some sort of 1/2 transp on the faces inside

cause that’s how the real model is
like the inside is dirty with some grey dark but with a gradient from base and up

so how can i simualte this in blender ?


anybody can help with this one ?

i tested a cube with double wall and trid to add some proc texture on outside face

but cannot get it to work ?

thanks for any help

have you tried adding a blend texture applied just to the alpha channel?

like this?


2010-08-06-01 (3).blend (156 KB)

i tried this one with a blend and some clouds

but not certain if practical
i mean the line between the 2 textures is too jagged

would preder may be do a alpha PNG with a smoother line and then apply

but don’t know if this can be done in blender or only GIMP?

see bottom of lamp the top part has some gradient transp
bottom is dark but a little bit transp but don’t really matter for this aprt
the top is more important for the look!